Rain or shine as 2019 becomes 2020?
Forecasting the weather is a tricky business. If asked whether the next 12 months through winter 2019 and on into 2020 will be very hot, very cold, very wet or very dry, I have to be honest and say “yes”. And as I would like to explain, that is not meant to be a tricky answer.
It is hard not to be biased by the sheer scale, intensity and duration of Don Valley flooding near our Sheffield office when making a meaningful prediction of what our climate and weather are likely to bring in the months ahead.
However, the trends behind climate change probably offer a more reliable clue. And knowing how to prepare for whatever is thrown at us as 2019 turns into 2020 is a definite advantage.
Year of extremes
My first approximate answer is that we will need hats, coats, wellies, plus swimsuits and sun-cream as storms become “wetter”, slower, more frequent, move northwards – and we see more “… brrr, Britain freezes” but also dry and hot “… phew, what a scorcher” headlines in the year ahead.
Will Christmas be white? Sorry, I’m not a bookmaker, but erm it wasn’t! Will we have a hard winter? Researchers say probably. Will 2020 see heavy rainfall and extreme flooding? Here, I have to say that the likelihood is “yes”, based both on our local 2019 experience and what new studies now tell us.
And as conditions become more extreme, preparations will have to move away from “resistance” towards “resilience” designed very carefully to bounce back from as yet unknown weather disasters.
But before looking at responsible and cost-effective preparation if the worst does come to the worst, it may help to look quickly at the four forces that could dominate our future – cold, wet, dry and hot.
Wet 2019 – cold early 2020
Summer 2019 was forecast to be a sizzler like 2018. But it rained and pretty much kept on raining as the jet stream travelling at 320 kph (200mph) six miles (10km) above us became an Atlantic hosepipe – “atmospheric river” – driven by larger-than-usual tropical storms.
The good news was no repeat of 2018’s mid-winter Beast from the East, when Siberian air coming in over Scandinavia led to Cairngorms temperatures of -140C, emptied high streets, disrupted travel, and saw the Bank of England forecast an economic growth cut.
But our luck is predicted to run out. The Beast could return in early 2020, University College London Department of Space and Climate Physics scientists have warned in the longest long-range forecast ever made using modern computer-modelling (https://discovery.ucl.ac.uk/id/eprint/10080518/).
Using solar and stratospheric signals, plus mid-ocean light, pressure and temperature conditions, they expect average January and February 2020 temperatures of 3.90C in the coldest winter since 2010, with only a “20% chance” of temperatures rising above 50C.
According to official figures, winter and spring 2018 saw 50,100 “excess” deaths in England and Wales, the highest since 1976 with many linked to flu and ill-health but also cold conditions. That is definitely something worth preparing against!
Rain, rain go away …
With winter woollies safely stowed away finally for another nine months – more or less – the next climate change-related problem property-owners and occupiers are likely to face is once again in many case flooding. In practical terms, we have three choices.
The first is to do nothing, save money in the short-term, but risk high long-term damage costs. The second is to build “hard” concrete defences to stop rising water levels. However, the third is to build “resilience” into our infrastructure in such a way that we can live with whatever the future brings. Choices two and three have up-front investment costs but also very important long-term gains.
In a moment I would like to look at practical preparation. But first I would like to review what prediction tools – old and new – we have at our disposal.
From seaweed to satellite data
Starting with “old”, dry seaweed hung outside overnight is said to be a good traditional weather indicator. If dry the day will be dry, if damp it will rain. If soaking wet it is probably already raining!
Should woodchuck Punxsutawney Phil made famous by the film Groundhog Day “sees his shadow” when woken from his hibernation on 2 February, it will rain for the next six weeks. Otherwise, expect fine weather.
Kakas are a New Zealand parrot. When they twist and squawk in the forest, Maori folklore predicts storms. Similarly, Kotukus are a heron; large numbers in the summer mean gales and a heavy winter. Meanwhile, when nimatanin shellfish on the Pacific Kiribati islands keep to shallow reef waters, expect good weather. If they hide, expect bad weather. The deeper they go, the worse it will be!
1. Flooding – more reliable prediction tools
Science has also created powerful “new” tools. Unfortunately, they are telling us that flooding is a growing menace.
A new European research report published in Nature (https://www.nature.com/articles/s41586-019-1495-6) says climate change is altering Europe’s flood patterns, with spring floods starting earlier.
The report maps out regions with large river flooding increases and explains how atmospheric moisture is nudging the path and spread of rainstorms north and westwards. It warns that without planning for increased flooding, existing defences could be overwhelmed.
Researchers tracked high river flows at 3,700 points from 1960 to 2010; in northern Europe, these increased by nearly 18% each decade, with Scotland, coastal France and Norway as hotspots; 100-year floods – 1% chance of happening in any given year – are now closer to 50-to-80-year events.
Compound flooding problems
Another study published by Science Advances (https://www.bbc.co.uk/news/science-environment-49731591) warns that Devon, Cornwall and the Bristol Channel will be hit by “compound-flooding” where storm surges and heavy rainfall generated the same low-pressure system out at sea – plus block drainage channels – cause damage property and injuries.
Modelling shows that compound-flooding currently affects some 3% of coastal areas every six years, a figure that could rise to 11% by 2100 made worse by a one-metre sea-level rise this century that will continue into the next.
Enzygo hydrology (https://www.enzygo.com/services/hydrology/)
At this point, I would like to describe briefly how our hydrology services help clients make responsible long-term plans as flood and drought conditions become more erratic. We take factors like probability and potential damage into a pragmatic investment-risk-benefit equation.
We also recognise that this balance is almost certain to keep on changing. Therefore, our recommendations and solutions wherever possible are designed to take in unknown future circumstances – resilience again.
Natural systems – While many local flood defences are ‘hard’, we also use SUDS schemes that duplicate natural processes to store, clean and return water slowly to the environment through swales, reed beds and soakaways. This creates attractively profiled landscapes with added amenity areas and habitat that are also important in water conservation for drier drought periods.
Methodology – Our systematic multi-disciplined approach starts with a Flood Risk Assessment followed by Flood Risk Modelling of fluvial, pluvial and tidal flooding. Our team also applies sequential and exception tests. For Drainage Modelling, our Surface Management Plans, SUDS schemes and Utility Assessment have helped to gain planning permissions for many developments.
Business continuity and life as usual – If conditions become more challenging, flood warnings and emergency evacuation plans are vital – no one wants disruption to supply chains, production, transport links and revenue. Our table top planning exercises and flood depth impact modelling are helpful here, as are our Mitigation and Flood Defence Assessments.
Expert witness – This director-level service has contributed to many successful appeals on grounds of hydrology and groundwater risk, drainage, geology and hydrogeology. We have also developed a site pollution index tool to calculate site pollution after flooding.
2. Drought – the climate change flipside of flooding
In June 2019, heavy rain created sinkholes on the M25 at a time when groundwater levels were much lower than normal after one of the warmest Easter weekends on record.
But dry ground could not soak up the downpour because, firstly, it was so intense, and secondly, water fell on a hard-paved urban area. Small rivers could not cope. The result was human-induced flooding during a drought that poured through homes and businesses.
As I have already mentioned, more generally SUDS is a powerful drought resilience tool.
3. Heatwaves – and fatalities
What other countries regard as summertime we tend to see as “heatwaves”, perhaps because to us “northerners” they are still sudden and unusual. However, climate change could make heatwaves 30 times more likely. The UK and many countries saw all-time high temperatures in 2019, and not just in the summer; the mercury hit 21.20C in London’s Kew Gardens in February – the hottest winter day on record.
Office for National Statistics (ONS) data identified an extra 1,473 deaths on 25 July, 2019’s hottest day, when 38.70C was recorded at Cambridge University Botanical Gardens. Public Heath England recorded 863 extra deaths in three 2018 heatwaves.
The London School of Economics says deadly heatwaves should be named like storms so people treat them more seriously. Some commentators believe climate change is the new 9/11 for insurance companies.
From the horse’s mouth
For businesses that need a calculated commercial assessment of the prospects of a hard snowy winter, bookmakers make their living through hard-nosed predictions. As of late November, William Hill offered odds of 6/1 for a white London Christmas Day
Good preparation is about evidence, probabilities and outcomes.
As explained above, we can choose to do nothing at low cost but with long-term negative impacts. Or we can resist and/or learn to accept climate change. That involves early infrastructure or design costs but longer-term security and peace-of-mind.
American theologian Reinhold Niebuhr (1892–1971) probably put it best in his famous request for “serenity to accept the things I cannot change, courage to change the things I can, and wisdom to know the difference.”
When it comes to flooding, preparation can make a very big difference.
Happy to talk at any time. Please contact me directly.